3GPP networks are beginning to support communications devices and/or customers with very different and/or special respectively specific characteristics, such as M2M (M2M: Machine to Machine) devices, etc. These classes of communications devices and/or customers may have different requirements from the network elements (for example eNodeB (eNB), MME, CIoT-BS, C-SGN) of a mobile communications network in terms of optional feature support, traffic characteristic support, availability, congestion management, ratio of signaling to user plane traffic, etc. Such requirements relate to radio related capabilities of the communications device (UE) and/or to core network capabilities of the communications device (UE), which are for example defined in 3GPP TS 36.331, Chapter 6.3.6 “Other information elements”, “UE-EUTRA-Capability” and relate for example to PDCP parameters, RLC parameters, RF parameters etc. It is supposed, that the classes of communications devices and/or customers will continue to increase. One cost effective mechanism for operators to support these different classes of communications devices and customers is to create separate dedicated core networks consisting of specialized core network elements that are designed and deployed to meet the requirements of these different communications devices and/or customers. It is cost-effective as the network availability or redundancy requirements may be easier met with different hardware and/or software than the existing network elements of a mobile communications network. Also, especially creating separate core network elements enables independent scaling or specific feature provisioning for specific communications devices and/or customers or traffic types and isolating specific communications devices and/or customers and traffic from each other.
In a mobile communications network according to LTE the mechanism to transport information regarding radio related capabilities of the communications device (UE) and/or regarding core network capabilities of the communications device (UE) is designed in a way that during an attach procedure, especially with RRC (RRC: Radio Resource Control), and the first TAU procedure (TAU: Tracking Area Update) to LTE the mobile communications network retrieves the UE capabilities from the communications device (UE), especially according to 3GPP TS 23.401, 3GPP TS 36.300, 3GPP TS 36.331 respectively 3GPP TS 36.413, which are herewith cited by reference, especially for purposes of supporting disclosure and the scope of the present invention. For subsequent RRC connections, MME (MME: Mobility Management Entity) provides these capabilities to the eNodeB (eNB) within an INITIAL CONTEXT SETUP message over so called S1 when the default bearer is setup. The mechanism is for example shown in 3GPP TS 36.300, chapter 18 “UE capabilities” (also compare enclosed FIG. 1).
For a mobile communication network according to CIoT, the core network elements (for example C-SGN) have to support a very large number of IoT communication devices which have very different traffic characteristics than for example communication devices that the EPC respectively EPS is currently supporting. The message sizes and traffic load in CIoT is much smaller (for example 20 bytes to 200 bytes), single/limited transfers (for example 1 to 2 packets per transmission/reception) and sent infrequently (for example several times a day) than the traffic model assumed for existing EPC traffic. Also, requirements for supporting respectively not-supporting seamless mobility are different.
Thus, the core network respectively core network elements of a mobile communication network according to CloT can have a simplified and different architecture from the existing EPC architecture according to LTE to cope with such communication devices (UE), especially including communication devices (UE) for NB-IoT respectively CIoT, like M2M devices respectively MTC devices and/or the like. The two options for developing the CIoT core network are to have the existing EPC support S1 interface while not modifying the existing EPC architecture, nodes and/or interfaces, such as MME, SGW, PGW, SII, S5, SIO, etc., or to have a modified core-network architecture for CIoT and have S1 as interface between the CIoT core network and the CIoT RAN. The CloT core network than only serves communication devices that attach to CIoT RAN.
For CIoT NB-IoT systems (NB-IoT: Narrow Band IoT) are designed within 3GPP, which especially intend to provide means for a much more efficient way to send respectively receive small amount of very infrequent data. 3GPP TR 23.720, which is herewith cited by reference, especially for purposes of supporting disclosure and the scope of the present invention, shows for example within Solution 2 one agreed way of doing it (compare for example chapter 6.2 of 3GPP TR 23.720). The enclosed FIG. 2 shows the corresponding message flow for mobile originated small data transmission according to 3GPP TR 23-720 Solution 2. As it can be seen from FIG. 2, after the attach procedure, which is an RRC connection establishment and from RRC perspective also comprises three messages (in FIG. 2 it is shown summarized as one step “0. Attach”), namely RRC connection request, RRC connection setup and RRC connection setup complete, there is no INITIAL CONTEXT SETUP message over S1 or a similar mechanism, with which the capabilities of the communications devices, especially radio related capabilities of a communications device (UE) and/or core network capabilities of a communications device (UE) respectively required and/or supported by a communications device (UE), could be transferred. Furthermore, the connection for small data delivery (Message 6 “Small Data Delivery, RRC connection release” in FIG. 2) might be released just after first downlink NAS message (Message 5 “Downlink NAS Message (NAS PDU)” in FIG. 2).
In spite of this, there is a need for a mechanism which allows operating a communications device (UE) in a mobile communications network, especially according to LTE or CIoT, whereby the capabilities of the communications device (UE), especially radio related capabilities of the communications device (UE) are as fast as possible available and usable at a network element, especially eNodeB (eNB) and/or CIoT-BS, of the mobile communications network providing a wireless access interface for the communications device (UE).